0
Inverse Definite Minimum Time Lag = IDMT relay
It's a electromagnetic type rotating disk relay.
Tripping time of relay decreases with increasing fault current.
see http://myweb.tiscali.co.uk/robert.booth/uni/docs/Power%20Supply%20Assignment%203.pdf
Wiki User
∙ 13y ago
Wiki User
∙ 15y agoIDMT: Inverse Definite Minimum Time
The term is generally used to describe relay (electrical switchgear) characteristics. IDMT relays have such tripping characteristics that, for a particular range of low values of current the tripping time varies inversely with the value of current. But beyond a certain current limit the tripping time becomes constant(definite) and causes tripping in minimum time. Hence the name Inverse/Definite Minimum Time. This type of characteristic is found in Overcurrent Relays.
Add your answer:
Earn +20 pts
What is IDMT stand for?
Inverse Definite Minimum Time
What is pick up of a relay?
The "pick up" of a relay is a setting at which the relay will begin to operate. Such as an overcurrent relay - if the pickup is set to 5A, when 5A is flowing through the relay, the relay will operate.
What is the difference between a relay and an auxiliary relay from constructionapplication poin of view?
I think aux relay is part of relay
Earth fault relay and an overcurrent relay Methods to energise an earth fault relay?
Earth fault relay and an over current relay Methods to energies an earth fault relay with simulation diagram?
What the Generator lockout relay?
generator lockout relay is a relay that the output of other relays energize this relay and its out put use for tripping of generator. this relay must be reset manually
What is dmt and idmt relay?
DMT relay stands for definitive mean time, and IDMT stands for inverse definitive mean time. In IDMT relay, there is a minimum time delay with magnitude.
How is a IDMT relay used to give protection against a phase to earth fault a phase to phase fault on a feeder?
As with any IDMT relay the higher the fault current the quicker the trip time.
What is the function of IDMT relay?
i working 66 kv and 220 kv substation. over substatin transformer and 66 kv sf6 bracker use i intersted for working of idmt realys with breacker tripping coil.
What is function of idmt relay?
i working 66 kv and 220 kv substation. over substatin transformer and 66 kv sf6 bracker use i intersted for working of idmt realys with breacker tripping coil.
What is lt idmt curve?
idmt curve
DIFFERENCE BETWEEN IDMT AND DMT?
The CT associated with the DMT, IDMT, inverse, very inverse and extremely inverse possess different characteristics. In particular, Inverse and IDMT CT’s have different operating points on their magnetic characteristics. i.e. Both have different saturation levels.
What is the difference between idmt and dmt?
idmt means inverse definite minimum time. so in this type of relay as the value of operand that is current increase time taken by the relay to operate decrease. higher the current lower is the time taken by the relay to operate. AND dmt definite minimum time (DMT) relay take its minimum time to operate regardless of the value of the current. The definite mean time lag in disc type EM relays is inverse to current as the disc is faster at higher current and hence the less time.Definite mean time lag is possible in static relays by setting the time lag.
What is IDMT stand for?
Inverse Definite Minimum Time
What is psm tsm for idmt relay?
PSM stands for Plug setting multiplier and can be found on the front of the relay module in the form of a scale . PSM = Actual or fault current in the relay / ( CT Secondary current X Amp setting in the relay) From the above value of PSM find the time in seconds from the front of relay panel scale i.e., PSM Vrs Time in seconds Miltiply the time in seconds with the TSM to find the tripping time for the relay for the specific value of fault current TSM = Time setting multiplier Relay Operating time = TSM x time in seconds <- as observed from the scale .
What afsc is 4n051c?
Aerospase Medical Service Journeyman, Independent Duty. Otherwise called IDMT.
What is idmt over current relay with different plug setting multiplier?
Any nonlinear load on a system generates harmonics. Exampes are the magnetic core of a transformer or equipment which uses rectifiers to produce direct current. The triplen harmonics are unpopular because they add on a three-phase system, so they produce current in the neutral, which a three-phase system in balance does not.
What is relay coil?
An electrical device, typically incorporating an electromagnet, which is activated by a current or signal in one circuit to open or close another circuit.Based on Characteristic the protection relay can be categorized as-Definite time relaysInverse time relays with definite minimum time(IDMT)Instantaneous relays.IDMT with inst.Stepped characteristic.Programmed switches.Voltage restraint over current relay.Based on of logic the protection relay can be categorized as-Differential.Unbalance.Neutral displacement.Directional.Restricted earth fault.Over fluxing.Distance schemes.Bus bar protection.Reverse power relays.Loss of excitation.Negative phase sequence relays etc.Based on actuating parameter the protection relay can be categorized as-Current relays.Voltage relays.Frequency relays.Power relays etc.Based on application the protection relay can be categorized as-Primary relay.Backup relay.Primary relay or primary protection relay is the first line of power system protection whereas backup relay is operated only when primary relay fails to be operated during fault. Hence backup relay is slower in action than primary relay. Any relay may fail to be operated due to any of the following reasons,The protective relay itself is defective.DC Trip voltage supply to the relay is unavailable.Trip lead from relay panel to circuit breaker is disconnected.Trip coil in the circuit breaker is disconnected or defective.Current or voltage signals from CT or PT respectively is unavailable.As because backup relay operates only when primary relay fails, backup protection relay should not have anything common with primary protection relay.Some examples of Mechanical Relay are-Thermal(a) OT trip (Oil Temperature Trip) (b) WT trip (Winding Temperature Trip) (C) Bearing temp trip etc.(a) Buchholz (b) OSR (c) PRV (d) Water level Controls etc.Float typePressure switches.Mechanical interlocks.Pole discrepancy relay.
